## Can I get rid of the CSGN function and make my ve...

r(t):= <t | t^(2) | (t^(2) )/(2) >

simplify(,symbolic)

diff(r(t),t)

The three lines above are part of a worksheet that computes unit tangent vector, unit normal vector and components of acceleration for a parametric curve r(t) ,  a standard Calc 3 lesson.

I am...

## Length of output exceeds limit of 1000000...

Hello,

I have one calculation and the result is "Length of output exceeds limit of 1000000"... What can I do with this error?

Thanks a lot.

## Help using rsolve...

Hi, I'm trying to use rsolve to solve the difference equaiton: y(n)-3*y(n-1)-4*y(n-2)=delta(n)+2*delta(n-1)  where deta(n) is the discrete delta function represented by charfcn[0](n).  The answer should be y(n)=(-1/5)*(-1)^n+(6/5)*4^n.  I'm getting the answer in terms of y(0) and y(1) and extra terms.  Can someone point me in the right direction?

## Tolerance Specification...

Is it possible to specify tolerances such as +10,-5 instead of just +-10?  In other words, can the high and low limits be different?  Thanks, Ratch

## X...

Fsolve solve for numeric when I put X as an parameter in one of the equation it get an error

restart;
y1 := 2*a*b^2-b+c-d-1 = X;
y2 := a^4+b^3-b^2+c-d+2 = 0;
y3 := a*b^2-b+c-d-3 = 0;
y4 := a^3*b^2-b+c-d^3+4 = 0;
fsolve({y1, y2, y3, y4},{a,b,c,d})

Error, (in fsolve) X is in the equation, and is not solved for

## 5) Look at the below code. It takes 7 seconds...

5) Look at the below code. It takes 7 seconds to make the call to yahoo finance 4 times
sequentially. The strange thing is that it takes the same amount of seconds to do the call
in parrallel....hummm very strange....what is the benefit of using the Task command then ??
I have 4 cores in my machine ie kernelopts(numcpus) returns 4 so it should be very fast.

restart:
with(Sockets):

X1 := proc (...

## Filling Matrix...

I want to fill a matrix m by m with elements

1) the elements under the diagonal comes from the expression

Gama:=(i, k)→evalf(((x[k]-x[i])*xdot[k]-(y[k]-y[i])*ydot[k])*dtheta[i]/((x[k]-x[i])+(y[k]-y[i])^2))

2) the elements in the diagonal comes from Lambada:=(i)→-sum(Gama, k=1..M), where i<>k

## installing maple problem!...

I've tried to install maple 10 in windows vista but it seems imposible the setup keeps saying this.."please wait, maple 10 is being configured for your system, this make take a moment..." i've left my computer on all night but the installation doesn't end...any ideas on how to solve this problem? thank you.

## Could you please explain the following:1...

Could you please explain the following:

1) str1 and str2 should be global variables right? I mean so we can call them
after the Create statements....

2) When I execute the below code and then call str1 and str2 I dont get any html output.
The " " are empty.....why?

restart:
with(Sockets):

X1 := proc () local str, sid, b;  global str1;

## Collect by differenatiation order...

My question is similar to the one referenced, but a bit more complicated.

Considering a PDE of order n, I would like it to be collected by the order of differentiation.

A simple example:

simplify(( (3+4*x)*diff(f(x), \$(x, 2)))+(5+4*y+z)*(diff(f(x), x))+(1+r+y)*f(x))

where the idea is to return to the form prior to simplification, including the sort by differentiation order.

After it is simplified, I can get the coeff of only the highest order derivative, as

but I dont understand where the output is saved...?!  Also should I use task or threads ?

restart:
with(Sockets):

X1 := proc () local str, sid; global b; str := "";

Write(sid, cat("GET /finance/historical?q=INDEXSP:.INX&histperiod=daily HTTP/1.0 \n\n"));

b := Read(sid); while b <> false do str := cat(str, b...

## minimize (z-Z) ^%T.E^-1. (z-Z)....

What's wrong?
I need to minimize (z-Z) T.E-1. (z-Z).
How can you see in the first Call to LSSolve worked. By introducing objectivejacobian I have problems

## Literature search for an implicit differentiation ...

Recently, I submitted for publication to a peer-reviewed math journal

a formula for the n-th order implicit derivative given an implicit function G(z,w)=0.

i.e. dz/dw = - Gw/Gz where Gw and Gz are partial derivatives of G with respect to w and z, respectively. Anyway, I proved the general formula for d^n z/ dw^n.   I have since proved the generalization of this to implicit functions of several variables, G(z,w1,w2,...,w(N))=0. A good mathematician...

## i need help in sloving pde equation and how to plo...

PDE:  utt=c2uxx+f(x,t)   ; f(x,t)=a*sin(2*pi*t/P)

BC: u(0,t)=0,u(L,t)=0;

IC: u(x,0)=0,ut(x,0)=0;

who can show me the steps by using maple? and i need help to plot the graph as well. thx!